He was living with his mum and working as a dish-washer. But he threw all he had into a brutal play that became a Scottish classic. The dramatist talks about the return of Knives in Hens – and writing an angry film about Lockerbie

Pop’s great miserablist gets a biopic, Scarlett Johansson has stripper trouble, Charlize Theron explodes into ultraviolence, and Union deserter Colin Farrell shakes up a girls school during the US civil war